240 weatherby vs 6mm-06

Can someone tell me the difference, if any, in these two calibers. I currently own rifles in .300 wby,270wsm,257wby, and 25-06. I would like to add a 6mm/.243 to my arsenal and had considered the .240wby. I have been hearing a bunch about 6mm-06 but to me they seem like the same thing. Sorry if this is a stupid question .

the .243 win is a good choice, as well as the others. not a stupid question.

as far as "where are you gonna get ammo", i guess we should all go back to the '06 and .223rem (that was sarcasm).

If I was you, i would lay out what i want to do with the rifle. decide if its going to be a practice rifle, a walking varmit rifle, a long range hot-rod, a predator rifle or a big game rifle. then think about how many rounds that your gonna send through it a year, and when you can afford a new barrel.